Data signatures are often used when attempting to identify or match sets of data without the need to compare full data sets. For example, computer virus signatures may be calculated by hashing known computer viruses and using the hash results as signatures. Unknown computer files can be hashed and the results may be compared to the computer virus signatures, and matches may indicate that the unknown files are computer viruses. Data signatures may also be used in other contexts, such as the detection of plagiarism and biometric identification using fingerprinting or DNA.